TWI466203B - Method for manufacturing semiconductor package substrate - Google Patents

Description

Semiconductor package substrate manufacturing method

The present invention relates to a semiconductor package substrate.

The present application claims the priority of the Korean Patent Application No. 10-2010-0067562, filed on Jul. 13, 2010, which is entitled "Manufacturing Method of Semiconductor Package Substrate", the entire contents of which are incorporated herein by reference.

With the development of the electronics industry, electronic components need to be characterized by high functionality and high integration. Based on this trend, the bump line spacing and substrate of ICs become ultra-fine and diverse.

Therefore, various processes for forming bumps on a substrate are currently being developed, and a process of printing a solder paste with a metal cover is most often employed.

However, the process of printing a solder paste with a metal cover plate has a problem that it is difficult to maintain the quality level, and the height and shape of the fine line pitch bumps are difficult to maintain at a high level. Therefore, in order to solve this problem, many research and patents have been revealed.

Traditionally, open squeegee modules, cover squeegee modules and closed squeegee modules have been known.

A conventional method of forming bumps on a semiconductor package substrate will be described below with reference to FIGS. 1 to 5.

First, referring to FIG. 1, the circuit board 14 is disposed on the vacuum panel 15 and then disposed under the metal cover panel 13. The metal cover plate 13 is provided with a solder paste 12 for bumps, and one side of the metal cover plate 13 is provided with a pair of squeegee plates 11 made of a urethane material.

Next, referring to Fig. 2, the solder paste 12 is rolled while the pair of squeegees 11 are pulled from one side of the metal cover 13 to the other side. The solder paste 12 is filled into the pattern of the metal cover plate 13 by the rotation of the pair of squeegees 11, so that the bumps are printed for the first time on the circuit board 14.

Next, referring to Figures 3 and 4, the pair of squeegees 11 are driven up and down in turn to change the direction in which the pair of squeegees 11 are towed.

Then, referring to Fig. 5, the pair of squeegees 11 are reversely pulled from the other side of the metal cover 13 to one side to roll the solder paste 12, so that the bumps are printed twice on the printed circuit board 14.

However, according to this prior art, since the pair of squeegees 11 are made of the same material, when they are used for a large-patterned circuit board (such as a package on package (POP)), the solder paste 12 It cannot be sufficiently filled in a large patterned circuit board, or its volume cannot be fixed even if the solder paste 12 is filled. Therefore, the problem of this prior art is that the bumps for flip chip bonding need to be printed separately, and the solder bumps for POP are formed by the process of bonding solder balls, so it is necessary to invest in high-priced devices and perform several additional processes. .

Accordingly, the present invention has been made to solve the above problems, and provides a method of manufacturing a semiconductor package substrate which can simultaneously form different types of bumps using a double squeegee mode.

Furthermore, the present invention is directed to a method of fabricating a semiconductor package substrate that reduces equipment investment costs and the number of process steps.

Furthermore, the present invention is intended to provide a method of fabricating a semiconductor package substrate which can simultaneously form bumps for flip chip bonding and solder bumps for POP.

One aspect of the present invention provides a method of fabricating a semiconductor package substrate, comprising: providing a circuit board under a cover plate for screen printing; and providing a pair of squeegee plates on the cover plate, including a first squeegee The plate and a second squeegee have different hardnesses; the first squeegee is towed from one side of the cover to the other side to first print a bump on the circuit board; and from the cover The other side of the board drags the second squeegee to the side to print a bump on the circuit board.

In the method, the first squeegee may be made of a material softer than the second squeegee, and the first squeegee may include a urethane, and the second squeegee may Includes a metal.

The cover sheet can be made of a photosensitive material.

In the initial printing, the pair of squeegees can be lifted from one side of the hood to the other while lifting the second squeegee. In the secondary printing, the pair of squeegees can be lifted by the other side of the hood to the one side while lifting the first squeegee.

After the second printing, the initial printing and the secondary printing may be performed more than once.

The method may further comprise the step of supplying a solder paste for the bump on the cover plate before or after the pair of squeegees are disposed.

The bumps may include a bump for flip chip bonding and a solder bump for a package on package (POP).

The various objects, advantages and features of the invention are apparent from the following detailed description.

The explanations of the nouns and vocabulary used in the specification and the scope of the patent application are not limited to the general meaning or dictionary definition, but should be interpreted according to the meanings and concepts defined by the inventors according to the meaning and concept of the technical scope of the present invention. The nouns and vocabulary used are used to describe the most appropriate method for practicing the present invention.

The objects, advantages and features of the invention will become more apparent from From the beginning to the end of the drawings, the same reference numerals are used to designate the same elements, and the redundant description is deleted. In addition, in the description, "first", "second", "one side", "the other side" and the like are used to distinguish one particular element from another element, but the configuration of such elements It should not be considered to be limited to these words. Further, in the description of the present invention, when the detailed description of the related art of the present invention obscures the gist of the present invention, the description will be omitted.

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

6 to 10 are schematic flow charts showing a method of manufacturing a semiconductor package substrate according to an embodiment of the present invention.

First, referring to Fig. 6, the circuit board 105 is placed on the printing table 106 using vacuum suction, and then placed under the cover plate 104 for screen printing. Next, the solder paste 103 for the bumps is supplied onto the cover plate 104, and then a pair of squeegees (including the first squeegee 101 and the second squeegee 102 having different hardnesses) are placed on the cover 104. The first starting point of one side, wherein the supply of the solder paste 103 and the configuration of the pair of squeegees are interchangeable.

The circuit board 105 may include a printed circuit board having a connection pad (such as a pad for flip chip bonding, a pad for POP, etc.) and a semiconductor substrate. Therefore, according to the method of the present invention, the connection pad may be used in a process step. At the same time, bumps for flip chip bonding and solder bumps for POP are formed.

The cover sheet 104 can be made of a photosensitive material. For example, a conventional dry circuit forming process is a dry film of a photosensitive material, which can be used as a cover sheet 104. Furthermore, in the general procedure for forming a circuit, in the case where a yellow light process is used to open an opening to be filled with a solder paste, a cover plate 104 can be used, which can be used because a dry film is used in a subsequent high temperature reflow process. The heat resistant material is used as a dry film.

When the cover sheet 104 made of a photosensitive material is used, the advantages of the bump height, the shape, and the like characteristics corresponding to the micro-line pitch bumps can be obtained.

The pair of squeegees are printed on the circuit board 105 by pushing the solder paste 103 into the openings of the hood 104. The pair of squeegees can be disposed on the squeegee brace off and can be moved up and down and left and right by the squeegee drive units.

In the pair of squeegees, the first squeegee 101 may be made of a material softer than the second squeegee 102, that is, the first squeegee 101 includes a urethane as a main component, and the first The second squeegee plate includes metal as a main component, so the first squeegee plate 101 can be softer than the second squeegee plate 102.

As described above, since the first squeegee 101 and the second squeegee 102 are made of materials of different hardnesses, various types of bumps can be simultaneously printed in one process step.

At the same time, the printing station 106, the circuit board 105, and the cover panel 104 can be aligned using methods well known to those of ordinary skill in the art.

For example, in order to achieve the above arrangement, the printing table 106, the circuit board 105 and the cover plate 104 may be respectively provided with calibration marks, and the calibration camera (such as a CCD camera) may be used to determine whether the alignment flags correspond to each other. . The alignment of the printed circuit board 106 and the circuit board 105 can be achieved at the same time as its setting.

In order to improve the accuracy of the calibration arrangement, a plurality of calibration flags can be formed in this paper. For example, the accuracy of the calibration arrangement can be improved by identifying at least two calibration flags by the camera for calibration. Moreover, the calibration flag can be provided in the blank area of the circuit board 105 and the edge of the mask 104 in the form of a calibration hole.

Then, referring to FIG. 7, the pair of squeegees are moved from one side of the hood 104 to the other side (as in the direction of the right arrow), and the first squeegee 101 of the squeegees is tilted in position. The first printing start point on one side of the cover plate 104 is towed, and the solder paste 103 is rolled by the first squeegee 101 into the opening of the cover plate 104 to be filled, so that it is printed on the circuit board 105 for the first time. Brass. In the initial printing process, while the first squeegee 101 is being towed, the second squeegee 102 is preferably lifted and moved.

Next, referring to FIG. 8, the first squeegee 101 is towed to the first printing end point on the other side of the hood 104, and then lifted, while the second squeegee 102 is tilted as shown in FIG. It is towed after the second printing start point on the other side of the cover panel 104, wherein the squeegee angle can be adjusted to suit the second printing direction (such as the leftward arrow direction). If necessary, when the remaining solder paste moved by the first squeegee has a sufficient content, the remaining solder paste is reused, and when the content thereof is insufficient, before or after the second squeegee 102 is dropped, The solder paste 103 is additionally applied to the mask 104.

Next, referring to FIG. 10, the pair of squeegees are moved from the other side of the hood 104 to one side (such as the arrow to the left), and the second squeegee 102 of the squeegees is tilted in position. The second printing starting point on the other side of the cover panel 104 is towed, wherein the solder paste 103 is rolled by the second squeegee 102 into the opening of the hood 104 to be filled, thus being secondarily on the circuit board 105. Print the bumps on the top. In the secondary printing process, while the second squeegee 102 is being towed, the first squeegee 101 is preferably lifted and moved. During the second printing, the initial printing process and the secondary printing process may be repeated more than once after the second printing.

Finally, when the second squeegee 102 reaches the second printing end point on the side of the hood 104, the second squeegee 102 is lifted and the hood 104 is removed, or the lower printing table 106 is used to make the hood The bumps from the printed circuit board 105 are detached, and the bump printing process is completed.

During the period, based on the type of component actually applied, a process well known in the related art, such as a reflow process or the like, may be performed before or after the cover plate is detached from the printed bump.

According to the present invention, since the double squeegee module (including the first soft squeegee, such as a urethane; and the second hard squeegee, such as a metal squeegee) is used, the bump printing process is performed twice. Various types of bumps can be formed simultaneously in one process, including bumps for flip chip bonding and solder bumps for POP.

The invention will be described in more detail hereinafter with reference to the subsequent embodiments, but the scope of the invention is not limited thereto.

Comparative example 1

A printed circuit board 14 including a pad for flip chip bonding and a pad for POP is provided. Next, as shown in FIG. 1, the printed circuit board 14 is placed on the vacuum panel 15 and then placed under the metal cover panel 13. The metal cover 13 is supplied with a solder paste 12 for bumps, and one of the urethane materials is placed on one side of the metal cover 13 to the squeegee 11.

Then, as shown in FIG. 2, while the pair of squeegees 12 are pulled from one side of the metal cover 13 to the other side, the solder paste 12 is rolled to fill the pattern of the solder paste 12 into the metal cover 12. In this case, the bumps are printed for the first time on the printed circuit board 14.

Next, as shown in FIGS. 3 and 4, the pair of squeegees 11 are driven to rotate up and down to change the direction in which the pair of squeegees 11 are towed. Then, as shown in FIG. 5, the pair of squeegees 11 are reversely pulled from the other side of the metal cover 13 to one side to roll the solder paste 12, so that the bumps are printed twice on the printed circuit board 14. . Figure 11 shows the shape of the bumps printed on the pads of the POP printed circuit board.

Example 1

A printed circuit board 105 including a pad for flip chip bonding and a pad for POP is provided. Next, as shown in Fig. 6, the circuit board 105 is placed on the printing table 106 by vacuum suction, and then placed under the cover plate 104 for screen printing. Next, the solder paste 103 for bumps is supplied onto the mask 104, and then a pair of squeegees (containing urethane squeegee 101 and metal squeegee 102 of different hardness) are placed in the hood. A first starting point on one side of the plate 104, wherein the supply of the solder paste 103 and the configuration of the pair of squeegees are interchangeable.

Then, as shown in FIG. 7, the pair of squeegees are moved in the direction of the right arrow, and the urethane squeegee 101 in the squeegee is tilted to the side of the cover 104 side. After a printing start point is dragged, the bumps are printed for the first time on the printed circuit board 105.

Next, as shown in FIG. 8, the urethane squeegee 101 is towed to the first printing end point, and then lifted, while the metal squeegee 102 is tilted to the second printing as shown in FIG. Starting point.

Then, as shown in FIG. 10, the pair of squeegees are moved in the direction of the left arrow, and the metal squeegee 102 in the squeegees is dragged by the second printing starting point, so that in the printing The bumps are printed twice on the board. Figure 12 shows the shape of the bumps printed on the pads of the POP printed circuit board.

Referring to Fig. 11, when the bumps were bi-directionally printed using the urethane squeegee as in Comparative Example 1, the solder paste could not be sufficiently filled in the pads for POP; conversely, referring to Fig. 12, as in Example 1 When the bump is printed by the double squeegee module containing the urethane squeegee and the metal squeegee, the solder paste can be easily filled into the POP pad, which can be used in the general bump forming process. At the same time, solder bumps for POP and bumps for flip chip bonding are formed without performing a solder ball bonding process.

As described above, according to the method of the present invention, since a pair of squeegees of different hardnesses are used, different types of bumps can be simultaneously printed in one process.

Moreover, according to the method of the present invention, since the solder ball bonding process or the like can be omitted, the equipment investment cost and the number of processes can be reduced.

Further, according to the method of the present invention, bumps for flip chip bonding and solder bumps for POP can be printed in the same process.

Although the present invention has been described in connection with the preferred embodiments of the present invention, various modifications, additions and substitutions may be made without departing from the scope of the invention as set forth in the appended claims. spirit.

The invention is intended to be within the scope of the invention, and the specific scope of the invention will be apparent from the scope of the appended claims.

105. . . Circuit board

106. . . Print station

104‧‧‧ hood

103‧‧‧ solder paste

101‧‧‧First squeegee

102‧‧‧Second squeegee

14‧‧‧Printed circuit board

15‧‧‧vacuum board

13‧‧‧Metal hood

12‧‧‧ solder paste

11‧‧‧Scraping board

The above and other objects, advantages and features of the present invention will become more apparent from

1 to 5 are schematic flow charts of a conventional method of manufacturing a semiconductor package substrate.

6 to 10 are schematic flow charts showing a method of manufacturing a semiconductor package substrate according to an embodiment of the present invention.

Fig. 11 is a photograph showing the state of printing of the solder bumps for POP formed in Comparative Example 1.

Fig. 12 is a photograph showing the state of printing of the solder bumps for POP formed in the first embodiment.

105. . . Circuit board

106. . . Print station

104. . . Cover plate

103. . . Solder paste

101. . . First squeegee

102. . . Second squeegee

Claims (8)

A method of manufacturing a semiconductor package substrate, comprising: providing a circuit board under a cover plate for screen printing; and providing a pair of squeegee plates on the cover plate, including a first squeegee and a second squeegee a plate, wherein the first squeegee is made of a material softer than the second squeegee; the first squeegee is towed from one side of the cover to the other side for the circuit board First printing a bump; and dragging the second squeegee from the other side of the cover to the side to print a bump on the circuit board. The method of claim 1, wherein the first squeegee comprises a urethane and the second squeegee comprises a metal. The method of claim 1, wherein the cover sheet is made of a photosensitive material. The method of claim 1, wherein in the initial printing, the pair of squeegees are lifted from one side of the hood to the other while the second squeegee is lifted. The method of claim 1, wherein in the secondary printing, the pair of squeegees lift the first squeegee while the other side of the hood is moved to the one side. The method of claim 1, wherein the primary printing and the secondary printing are performed more than once after the secondary printing. The method of claim 1, further comprising: supplying a solder paste for the bump on the cover plate before or after the pair of the squeegee is disposed. The method of claim 1, wherein the bump comprises a bump for flip chip bonding and a solder bump for a package on package (POP).